This manuscript has introduced an algorithm based on current signals and frequency rate change (ROCOF) to identify islanding events. Current is analyzed by the use of Stockwell transform (ST) at 3.84 kHz sampling frequency (SF) and a median of absolute values of every column of output matrix (CSIRI) is computed. Rate of change of CSIRI (ROCOCSIRI) is computed. Proposed current based islanding recognition index (IRIC) is computed by multiplying ROCOF with CSIRI & ROCOCSIRI and a weight factor (WC). Threshold values THI1 & THI2 are selected 100 and 3000 for IRIC for identifying the Islanding condition. These are also effective to differentiate islanding conditions from non-islanding events which include both the faulty and operational events. Magnitude of IRIC is greater than 3000 for the faulty events and lower than 100 for operational events. For islanding events magnitude of IRIC falls in between the 100 and 3000. Algorithm is effective to identify and classify the events in three categories which are islanding events, faulty events and operational events effectively. Study is realized in MATLAB/Simulink scenario.

The higher frequency electromagnetic (EM) emission in low voltage power systems is rising continuously due to the increasing use of modern electronic devices. The electronic ballast of a compact fluorescent lamp (CFL) is one of the sources of conducted EM emission in the power system. Conducted EM emission measurements are performed on compact fluorescent lamps (CFL) in the range of 2–150 kHz and compared with simulation results. The LTSpice simulation of typical 11W compact fluorescent lamps is used to analyze the measured values. Comparisons are made in both the time and frequency domains. The EMI filter in the ballast circuit can reduce the level of high-frequency EM emission. However, in order to get a more accurate result, it is necessary to find out the main cause of conducted EM emission in the ballast circuit, as the HF distortion spreads through the LV network in current signal between electronic devices.